Hydraulic load test device

ABSTRACT

A hydraulic load test device for examination of load test pieces by pull, pressure or bending, provided with hydraulic elastic steel cushions, inserted between crossbeams of a mobile frame arranged slidable along posts and between a crossbeam, connecting both posts of the test device within an opening of the frame.

m mum @mm Wmmnl [151 mm wn Zajic [451 Feb 22, mm

[541 mnnmmec mm "mm" mwm jfiglereneee Cfilled [72] Inventor: Vladimir Zajic, Plz en c zechoslm illge N TED STATES PATENTS 73 Assignee: sn -mm fl P126, 1,905,535 4/1933 Giesler ..92/37 X czecmsmaka FOREIGN PATENTS OR APPLlCATlONS [22] Flled: Apr. 3, 11970 318,481 2/1957 Switzerland 73/93 [2!] Appl. No.1 25,4116

Primary Examiner-Jerry W. Myracle ..w m-. AtmmeyRichard Low and Murray Schaffer [30] Fun-elm Applfimmnu Prim-filly I 1 CT Apr. 10, 1969 Czechoslovalua ..2528/69 A hydraulic 103 d test device for examination of load test pieces by pull, pressure or bending, provided with hydraulic [52] IU.S. Cll .13/93, 92/37 elastic steel Cushions, inserted between crossbeams ofa [51] f m 3/10 bile frame arranged slidable along posts and between a cross- [58] lFleldl of Search l ..73/97, 93; 92/37 beam, connecting both posts f the test device Within an opening of the frame.

5 Claims, 3 Drawing Figures MHmzz m2 SHEET 1 OF 2 INVENTOR VLHD/M/R ZnJxc HYDRAULIC LOAD TEST DEVIEE BACKGROUND OF THE INVENTION This invention relates to a load test device for examination of load test pieces by pull, pressure or bending and particularly for examination of larger test pieces according to a predetermined program.

The individual elements of similar load test devices for tests with larger test pieces are exposed to extraordinary stresses in the course of performing different tests. As these tests are rather expensive, the load test device must operate reliably according to a predetermined program whether tests by pull, by pressure or by bending are concerned.

Most of actually used similar test devices operate with pressure sources using hydraulic cylinders and pistons. The construction of similar machines is due to the high working pressures and are rather bulky and heavy and therefore also expensive. There are also difficulties with regard to the packing of the piston rods and ofthe pistons themselves at high operating pressures.

SUMMARY OF THE INVENTION it is an object of this invention to provide a load test device ofthe kind described which would allow a less bulky construction than actually used devices.

It is another object of this invention to enable an easy performance of tests according to a predetermined program.

it is still another object of this invention to eliminate to the highest possible degree difficulties with packing of elements which are exposed to high hydraulic pressure.

Bearing these and other objects in mind, there is provided a load test device with an open mobile frame, preferably of rectangular shape, with an upper and lower crossbeam, slidable along posts, connected at the top by a crossbeam, with a second crossbeam connecting the posts within the opening of said slidable frame and with sets of hydraulic elastic steel cushions inserted between the second crossbeam connecting the posts and the upper and lower crossbeam respectively of the slidable frame and with means for supporting the test piece between the slidable frame and a stable part of the load test device.

DESCRIPTION OF THE DRAWINGS An exemplary embodiment ofa load-testing device according to this invention is schematically illustrated in the accompanying drawings, where H6. 1 is an elevation of the machine with parts in vertical section,

FIG. 2 is a cross-sectional top view along a plane indicated in FIG. 1 by the line ll-ll,

H0. 3 an elevation of the central part of the machine at a larger scale with indicated means controlling the pressure in the steel cushions.

DESCRIPTION OF PREFERRED EMBODIMENT With reference to FIG. 1, the load test device comprises a baseplate 10, to which four vertical posts 11 are fixed, which are connected at the top by a first removable crossbeam 2 which remains fixed during the course of operation of the testing device. The position of the crossbeam 2, however, with respect to the posts 1 and 2 can be made adjustable prior to start the tests. An open frame 6, substantially of rectangular shape, comprising an upper crossbeam 3, a lower crossbeam 5 and two lateral walls 11, is guided slidably by the posts 1. The upper crossbeam 3 and the lower crossbeam 5 of the frame 6 are provided with holes 12 for free passage of the posts ii. The first crossbeam 2 is provided with a suitable cavity 113 in which is inserted the head of a test piece 9, which head is usually T- shaped. A similar cavity M for the other end of the test piece is provided in the upper crossbeam 3 ofthe frame ti.

A second crossbeam t is fixed to the posts l in their lower half. within the opening of the frame a, and serves as support for two sets 7 and 8 of hydraulic elastic steel cushions resting with their other surfaces against the upper crossbeam 3 and the lower crossbeam 5 respectively of the slidable frame is.

The internal spaces of the steel cushions 7 and ii are individually connected by way of spring-loaded return valves 17, 18 to conduits l5 and 16 respectively, supplying a suitable pressure medium, for instance oil to the cushions 7 and 8. The conduits l5 and 116 are connected to a sliding valve l9 which alternately connects one set 7 or ii of the spring cushions to a pressure conduit 20 while the other set is connected to a conduit 21 or 22 leading to the waste.

The described device operates as follows:

The test piece 9, suspended or supported within the cavities l3 and lid of the first crossbeam 2 of the posts l and of the upper crossbeam 3 of the frame 6, is exposed to pressure or pull generated by one of the sets '7 or ii of hydraulic elastic steel cushions whereby the stress of the force transmitted to the test piece 9 is taken over substantially only by the first crossbeam 2, by the second crossbeam i and by the posts ll, all these elements remaining stable in the course of the whole test.

The hydraulic medium is supplied to the steel cushions 7 or 8 by way of the slide valve 3.9 according to a predetermined program, which can be easily maintained by adjusting the pressure in the pressure conduit 20. As the cushions are individually connected to the supply conduits 11% or i s by way of return valves 17 or iii, an occasional failure of some cushions need not cause the failure of the whole device, as it is automatically disconnected from the pressure supply.

In operation always one set 7 or 8 of cushions is exposed to pressure, while the other set is connected to the waste depending on the position of the slide valve 19. In the neutral position of the slide valve indicated in FIG. 3 none of the sets '7 or 8 of cushions is connected to the pressure medium and the machine is inoperative.

As the different elements of the device are stressed rather favorably, the construction of the device can remain relatively light, so that the cost of the device is equally reduced while the control is easy and reliable.

I claim:

l. A hydraulic load test device comprising in combination:

a baseplate,

a number of vertical posts,

a first crossbeam connecting the posts at their tops,

a second crossbeam connecting the posts in their lower halves,

a frame comprising an upper crossbeam, a lower beam and two lateral walls,

the upper and lower crossbeam of said frame provided with openings for free passage of the posts through said openings,

enabling a free sliding movement of the frame along the posts,

the lateral walls ofthe frame remaining beyond the posts,

the frame encompassing in the assembled state of the device the second crossbeam of the posts,

hydraulic elastic steel cushions provided between the second crossbeam of the posts and the upper and lower crossbeam of the frame respectively,

means for supporting both ends of the test piece in the first crossbeam of the posts and in the upper crossbeam of the frame,

means for individually supplying and discharging a pressure medium to said steel cushions,

a pressure conduit for the pressure medium serving both for the supply and removal of the pressure from the steel cushions,

each of the steel cushions being connected to the pressure conduit by means of an automatic disconnect valve.

2. A hydraulic load test device comprising means for supporting a test piece: between a pair of opposed hydraulic pressure assemblies, each of said assemblies comprising a plurality of axially superimposed closed chamber members each semblies is movably mounted on a base frame for reciprocation toward and away from said test piece.

5. The device according to claim 3, wherein each of said cushion members is provided with an associated regulating valve, each valve being connected to a common conduit having valve means connected to the source of hydraulic media for selectively pressurizing one or the other of said assemblies. 

1. A hydraulic load test device comprising in combination: a baseplate, a number of vertical posts, a first crossbeam connecting the posts at their tops, a second crossbeam connecting the posts in their lower halves, a frame comprising an upper crossbeam, a lower beam and two lateral walls, the upper and lower crossbeam of said frame provided with openings for free passage of the posts through said openings, enabling a free sliding movement of the frame along the posts, the lateral walls of the frame remaining beyond the posts, the frame encompassing in the assembled state of the device the second crossbeam of the posts, hydraulic elastic steel cushions provided between the second crossbeam of the posts and the upper and lower crossbeam of the frame respectively, means for supporting both ends of the test piece in the first crossbeam of the posts and in the upper crossbeam of the frame, means for individually supplying and discharging a pressure medium to said steel cushions, a pressure conduit for the pressure medium serving both for the supply and removal of the pressure from the steel cushions, each of the steel cushions being connected to the pressure conduit by means of an automatic disconnect valve.
 2. A hydraulic load test device comprising means for supportiNg a test piece between a pair of opposed hydraulic pressure assemblies, each of said assemblies comprising a plurality of axially superimposed closed chamber members each adapted to be pressurized with a hydraulic media and means for independently regulating the pressurization of said chamber members to activate one or both of said assemblies.
 3. The device according to claim 2, wherein each of said chamber members comprises a cushion formed of flexible steel and said assembly including spacer members axially arranged between adjacent cushions.
 4. The device according to claim 3, wherein each of said assemblies is movably mounted on a base frame for reciprocation toward and away from said test piece.
 5. The device according to claim 3, wherein each of said cushion members is provided with an associated regulating valve, each valve being connected to a common conduit having valve means connected to the source of hydraulic media for selectively pressurizing one or the other of said assemblies. 